4. EXCEPTIONS › 4.3 Detailed Exception Descriptions › 02151: Average Device IOS Queue Time Exceeds Max

02151: Average Device IOS Queue Time Exceeds Max

FILE: Logical Control Unit Activity File
SAS FILE NAME: DAYS.SCPLCU01
SOURCE LOCATION: prefix.MICS.USER.SOURCE(DYRMFEXC)

SEVERITY: Impacting            (SEVERITY='I')
MANAGEMENT AREA: Performance   (MGMTAREA='PERFORMANCE')

PURPOSE:  Identify logical control units with excessive I/O
delays due to IOS queuing.

RATIONALE:  I/O operations delayed by IOS queuing indicate a
possible I/O bottleneck, resulting in lower throughput or
elongated response times in I/O-sensitive online systems.

DEFINITION:  This exception is detected when the average
queue time of waiting I/O operations exceeds the installation
defined maximum.

EXCEPTION STATEMENTS:  The SAS statements identifying the
exception situation and describing the condition are stored
in the source member named in SOURCE LOCATION and are
described below:

/* ***************************************************
**  02151 AVERAGE DEVICE IOS QUEUE TIME EXCEEDS MAX **
*************************************************** */
IF LCUAVIOS GT queue-time
 THEN DO;
  EXCCODE='02151'; SEVERITY='I'; MGMTAREA='PERFORMANCE';
  EXCDESC1='AVERAGE DEVICE IOS QUEUE TIME EXCEEDS MAX';
  EXCDESC2='Q TIME=' !! PUT(LCUAVIOS,5.1) !!
          ', LCUID=' !! LCUID;
  LINK HIT;
END;

THRESHOLD MODIFICATION:  The user should modify the value of
queue-time according to the following convention:

queue-time - The maximum IOS queue time in seconds is
specified.  A threshold of 15 milliseconds would appear as:

LCUAVIOS GT .015